Flags flew at half-staff at fire stations around the city Saturday as the Atlanta Fire Rescue Department mourned the loss of two firemen — one a newlywed, the other a father of triplets — who died within 24 hours of each other.

Atlanta Fire Chief Kelvin J. Cochran said the department is reeling over the deaths of Jermaine Hall and Sgt. Frank Guinn. Guinn was killed Friday in a bike accident in New Orleans while training for a triathlon. Hall died Saturday of a brain aneurysm.

The two men, described as “up-and-coming leaders of the department,” worked on the same shift, though at separate stations, and their shifts were on duty when the news came of their deaths.

“It is unusual to lose a firefighter under these circumstances, but to lose two within 24 hours that are on the same shift is pretty devastating emotionally to our members,” said Cochran.

Hall, 24, suffered the aneurysm early Friday morning, Cochran said. He was transported to Kennestone Hospital, where he died in the predawn hours of Saturday.

Hall joined the department two years ago and worked at Station 29. Cochran described him as a very charismatic young man who was trying aggressively to learn the ropes. During his last work shift, he had successfully completed the training to become an engine driver — an effort that usually takes firefighters three years or longer, Cochran said. Hall was married in October.

Guinn, 36 and a nine-year veteran of the department, worked at Station 21 as part of a special operations team that handles building collapses, high angle rescues, confined space rescues and trench collapses. He was in New Orleans training for a triathlon that was to take place this weekend when a motorist struck him and his brother-in-law as they were riding their bicycles.

Guinn’s brother-in-law was in critical condition Saturday. Guinn’s family, including his wife and triplet 7-year-old girls, traveled to New Orleans, Cochran said.

The people who worked with Guinn bragged about how he never said no and often volunteered to do the toughest jobs.

“As a triathlete, that says a lot about his dedication to being physically fit for his job and his commitment to wellness away from the job,” Cochran said.”He wanted to be capable of responding to any type of call, and he wanted to have the skills and abilities to contribute to whatever his crew needed.”

Details about the services were not available Saturday afternoon.